The present invention relates to communications gear. More specifically, it relates to performing system diagnostics on communications equipment.
Communications equipment used for data networking, such as cable modem equipment, is typically located in remote or difficult to access locations. These locations tend to have limited space for the use of diagnostic equipment used to test communications equipment and isolate faults.
Examples of communications equipment used for data networking are the telecommunications systems and cable television systems that have provided various types of services to the public for many years. The public demand has grown steadily for new types of networks. Currently, an estimated 95 million homes in the U.S. alone are wired for cable, and about 97% of U.S. households have access to cable. As cable television systems have become requisite, so have the broadband communications networks systems using cable modems. Cable TV (CATV) systems use either fiber optic cable or more typically, a HFC (hybrid fiber coaxial) cable combination, to deliver information into the home. Home access via coaxial cable, rather than a pair of copper wires, provides a much wider bandwidth. A telephone voice connection requires less than 4 kHz of bandwidth, while a television channel occupies a 6 MHz, or 1500 times as much. By using networking technology the cable operator or a broadband Internet Service Provider can use most of the bandwidth of a dedicated TV channel achieving a downstream data rate up to 38 Mbps which is hundred times faster than telephone technology. With proper repeaters, coaxial cable systems can easily support several GHz of bandwidth.
As cable television systems have become wipespread, so have the broadband communications networks systems using cable modems. Current internet access via 28.8 kbps, 33.6 kbps, or 56 kbps modem is referred to as voiceband modem technology. Like voiceband modems, cable modems modulate and demodulate data signals as well. Cable modems incorporate more functionality suitable for high-speed internet services. The data from the network to the user is referred to as downstream, whereas data from the user to the network is referred to as upstream in a cable network. The upstream and downstream data rates may be flexibly configured using cable modems to match subscriber needs. Cable modems use either a standard telephone line or a QPSK/QAM (quaternary phase shift keying/quadrature amplitude modulation) modem over a two-way cable system to transmit data upstream from a user location to the network.
In one cable modem implementation, the cable company supplies cable television, regular phone and internet services. To operate a cable modem, the subscriber will first need a cable access unit (CAU) installed at the cable entrance to the house. The CAU bridges the cable and separates the low-frequency phone access from video signals on the downstream path (to you) and injects telephony signals into the upstream path (from you). The CAU features standard telephone interface connectors to accommodate a conventional telephone and a coaxial connection for the cable interface. A cable modem that is located near a computer will connect the subscriber""s computer to CAU in order to communicate with online services. The modem typically offers throughput speeds of up to 10 Mbps per user in the downstream direction and 700 kbps or more in the upstream direction.
In another cable modem implementation, currently offered by a TV cable service provider, a special network card has to be installed in the user""s PC. The card is connected to the cable modem, which is located next to the computer. The incoming cable is split in two, one going to TV sets as before, the other feeding the cable modem. In this implementation, no regular phone service is provided over the cable. When users turn their computers on, they are immediately connected to the internet with no dialing required.
When providing phone service, the cable operator will need some additional equipment at the head-end of the CATV system, a CMTS (cable modem termination system) to combine voice-band telephone channels and pass them to a switch, and the CCU (cable control unit) to communicate with the CAUs to act as a protocol converter from the cable plant to a local telephone office. It allows the cable operator to integrate telephony and enhanced data services with the existing CATV signals. At the head-end is also the CAB (cable access router) which provides an interface between a hybrid fiber/coaxial transmission system and local and remote TCP/IP (transmission control protocol/internet protocol) networks such as the internet.
Data from individual users is filtered by upstream demodulators or telephone-return systems for further processing by a CMTS at the cable head-end. A CMTS can be described as a data switching system designed to route data from all the cable modem users over a multiplexed network interface as well as from the internet. Therefore, CMTS is an important support of data services that integrate upstream and downstream communication over a cable data network. Operational tasks of monitoring, provisioning and testing of various components of a CMTS are required to configure and manage a CMTS.
There is a need to evaluate the present operating states of the network equipment for diagnostic capability and equipment security. As noted above, the cable environment has limited space for diagnostics equipment since much networking gear is located in remote locations. A network trouble shooter must carry, at minimum, a laptop computer to the remote site to display equipment status by accepting commands and configurations for the equipment. Although notebook computers are smaller, a more practical and convenient diagnostic method is needed.
In the conventional art, a network technician typically carries a laptop computer to the remote site. The laptop computer is plugged into the network equipment to be tested. The laptop computer is used to display the equipment status and to accept command inputs and configuration data for the equipment. However, it is often difficult to access the network equipment in order to plug the laptop computer into the network device.
Therefore, the needs remains for a more convenient method of connecting to network equipment for performing testing and diagnostics.
The present invention is directed toward a method for testing and diagnosing network equipment using a hand-held computer that communicates with the network equipment using a wireless connection.
In a cable television system, the headend CMTS (Cable Modem Termination System) takes advantage of a high speed communications platform to allow cable television operators to build high-density, highly scalable communication system for data-over cable services. The central component of the CMTS is the CAR (Cable Access Router) which offers routing from the internet to the RF (radio frequency) network. The CAR and NIC (Network Interface Card) work together to provide RF output in one 6 Mhz, DOCSIS (Data Over Cable Service Interface Specifications) compliant data cable channel. The CAR and the URC (Upstream Receiver Card) operate together to process and route all upstream data sent from cable modem and to schedule the broadcast of MAC (Media Access Control) messages required for cable modems to initialize and register with the CMTS.
According to an exemplary embodiment of the present invention, a cable modem in a cable modem television system registers with the head-end CMTS (Cable Modem Termination System) to establish a data connection to the cable television system high speed communications platform. Preferably, the cable modems accessing the CMTS are compliant with the DOCSIS (Data over Cable Systems Interface Specification) standards. When cable modems cannot successfully register with the CMTS of the CAR, then CLI (Command Line Interface) commands can be utilized to obtain the connection status of the cable modem and troubleshoot the registration failure of the cable modem in order to assist in modem installation. According to this embodiment, a handheld computing device is interfaced with the cable modem in order to transmit CLI commands and receive responses to identify modem status and error messages.
According to another embodiment of the present invention, the handheld computing device, such as a Palm III PDA, can be interfaced to the networking equipment such as the CMTS or cable modem to provide configuration, monitoring or diagnostic capability. The handheld device can be interfaced with the CMTS by several different methods. In the exemplary embodiment, the handheld device is interfaced is interfaced to the CMTS device via an Infrared Data (IrDa) port on the Palm III. According to another embodiment, if the IrDa port is not available on the equipment, the PDA can also be connected to the equipment via serial connection or LAN (local area network) port.
In any connection method, the PDA may be running diagnostics software, configuration software or terminal emulation software to configure and monitor the network equipment. In the cable environment, much networking gear is located in remote locations which tend to have very limited space for diagnostics and equipment. In the current state of technology, a network trouble shooter must carry at minimum a laptop computer to the remote site for use in displaying equipment status by accepting commands and configurations. The portability of a handheld device such as a Palm device is uniquely advantageous for trouble shooting network equipment such as cable modems. The portability of a handheld device such as a Palm computer is uniquely advantageous for on-site installation and troubleshooting of network equipment.
Palm also supports fundamental DOCSIS programs which can program modem configuration and act as a network manager to modem SNMP (simple network manager protocol) agent. PDA can also be used to transfer a previously developed application of software with a stored set of CLI (command line interface) configuration commands and data without having to reenter command lines for configuration and MIB (management information base) support for SNMP (simple network management protocol). Remote software can also be downloaded over an IR port, LAN port or serial port to perform load updates. The software on the PDA also has the capability of converting collected network data into graphical form, which can be useful for analysis.